My first kitty was a mature Siamese male. He was a stray that we adopted. He was used to going out, and faithfully came home every night. However, he was bad.
We lived in Navy housing, which was townhouses. It was in Pensacola, and during nice weather people left their doors open (no screen doors). So our kitty just visited whatever houses he wanted. They were all the same layout inside, so he knew his way around. He would go upstairs, open the hall linen closet (they had louvered doors), jump up to the towel shelf, lay down, and close the door.
Our neighbors did NOT enjoy opening up their closet doors and seeing two bright eyes staring at them. (He caused a few near heart attacks!)
When he wanted to come back into our house, he would plaster himself like a spread-eagle bat on our window frame, or he would dangle from the front door knob and twist it back and forth. He was scary.
All our other cats after him were indoor cats (we learned our lesson).